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Blown Insulation | How Far Can It Be Blown?

The ability to blow in loose-fill insulation makes the installation process much faster. But there are some limitations—or, at least, practical considerations—as the blower machine sits outside the house with a hose running up to the attic, and the attics themselves can extend quite far.

There are several factors affecting how far insulation can be blown: the distance from the outside to the attic, the type of insulation, the equipment used to blow the insulation, the presence of obstructions, and how proficient the installer is with the machine.

Fiberglass insulation can reach further than cellulose, but mineral wool is even better. A more powerful blower increases the distance insulation can travel and can reduce the efficiency penalty of longer hoses. However, don’t forget about attic obstructions and the installer’s skill level.

Factors Affecting Distance of Blown Insulation

Distance From Outside

The hose needs to run up into the attic while the blower machine typically sits outside, which is part of the convenience of not having to fit everything into the small space.

While a professional may decide (from their expert knowledge and experience) to have the machine inside the attic, you should not do this on your own.

If you are using a gas-powered blower, then having it in the house means that you are releasing the exhaust air into a confined space. This can have health consequences.

The machine is also likely to be loud when running. Exposure to loud noises over an extended period of time can be damaging to your hearing.

In general, manufacturers recommend that the hose not exceed 100 ft for optimal performance, which is the standard length that comes with rental machines.

This should be long enough for most homes, although you have to consider the fact that the path to the attic may not be a direct one.

Moreover, if you just make it to the attic with the allowable blower hose length, then this affects how far into the attic you can blow the insulation.

You can get a longer hose, or you might be able to add extra pieces to some to extend them but then you also have to consider the disadvantage of using a longer hose.

A longer hose can reduce the amount of pressure that the insulation encounters as it travels through the hose, which can reduce the distance that the insulation can be blown out of the hose. However, some machines may be able to handle longer hose lengths or larger diameter hoses.

Type of Insulation

Different types of insulation have different densities and weights, which can affect how far they can be blown.

The size of the insulation particles can also affect how far they can be blown. Typically, smaller particles can be blown further than larger particles because there is less inertia to overcome.

Yet, you also have to consider how aerodynamic the shape is. Think about throwing a leaf vs a paper airplane. The feather is lighter, but it is not aerodynamic, so the paper plane will travel further with the same amount of force applied. 

Blown In Insulation | Is It Safe?

Blower Equipment

The blower machine that is used can also affect the distance insulation can be blown.

Consider the power that it can generate: a more powerful blower machine can blow insulation farther than a less powerful one.

Then there’s also the diameter of the hose.

Firstly, a larger diameter hose can generally blow insulation further than a smaller diameter hose. This is because a wider hose can move more air and insulation material through it at a faster rate than a smaller hose, which allows the insulation to be blown further.

Secondly, a larger diameter hose can also reduce the amount of friction that the insulation encounters as it travels through the hose. This can help to prevent clogs and blockages, which can reduce the distance that the insulation can be blown.

Insulation blower illustration

Finally, you need to take into account the age and condition of the machine. It may be rated at a certain power but will not function at that level. Any cracks or sharp dents (or kinks) in the hose can result in a loss of pressure and an increase in friction, respectively.


Obstructions in the attic, such as ductwork, wiring, pipes, and dividers can also affect how far insulation can be blown.

If there are many obstructions in the attic, it may be difficult to blow insulation a great distance. The machine may be capable of sending the insulation to the far reaches of the attic, but this can be inhibited if the insulation’s travel is interrupted by these structures in the attic.

They can slow, if not stop, the movement of the insulation and also possibly alter its arc of trajectory, meaning cannot reach as far.

The trajectory can also be influenced by the height of the roof and the presence of bends and corners around which the blower hose would have to be maneuvered. 

Proficiency of Installer

Of course, the last factor to consider is how much experience the installer has with the machine.

If you have it done by a professional team or someone who knows exactly how to work with the blower, then you can get the most out of the blowing distance.

If you are attempting to DIY the blow-in process since you can rent the blowers, you might not get the best results straight away.

Getting the optimal performance from the machine involves knowing how to adjust the settings and components as needed and how to hold and move the hose to get the best coverage.

Having an assistant is also helpful, so you don’t need to keep running back and forth to add more insulation to the machine.

Thankfully, like those below, there are videos available that offer tips, tricks, and basic information on how to use these blowers:

Distances Traveled By Insulation Types

We reached out to an insulation installation company to ask them what insulation travels the furthest.

According to Standard Insulating Company, fiberglass is the easiest material to get the furthest. This is between cellulose and fiberglass, the two types of blown insulation used by the company.

Depending on the power of your blower machine, reportedly, fiberglass insulation can be blown up to 20-25 ft, making it a popular choice for attics with limited access.

Cellulose insulation, on the other hand, can reportedly only be blown up to 12-15 ft due to its heavier weight.

Hose blowing cellulose insulation and fiberglass insulation illustration

Loose-fill mineral wool insulation can reportedly be blown up to a distance of 30-40 ft when installed using a blowing machine. Even though it can travel further than fiberglass, it is not as commonly used as fiberglass or cellulose.

Note: I was unable to verify these exact distances with multiple sources, meaning there may be some inaccuracies. Although, based on the composition of the materials, cellulose will travel a shorter distance than fiberglass, and mineral wool’s aerodynamic properties mean it travels further than both.

The distance it can be blown may be the deciding factor for which insulation material to use.

If so, you need to make sure that you can accommodate the correct thickness of the material to achieve the required R-value.

If there is some problem with this, you might have to choose the insulation material based on what will fit in the attic to achieve the R-value and then just manually install the blown insulation in the furthest parts of the attic. 

Spray Foam as an Alternative

Some newer insulation materials, such as spray foam insulation, can be blown up to 50 ft or more (again, reportedly). This is because spray foam insulation expands as it is sprayed, allowing it to cover a larger area with less material since it helps you out by moving into all nearby gaps and spaces.

Experts at Retro Foam of Michigan report that spray foam can expand up to 100 times the original volume, so you don’t have to manually fill all the gaps.

However, spraying spray foam is not the same process as blowing loose-fill insulation. It requires different machines and techniques and will need professional installation to be safe.

Solutions for Limited Attic Access

If you have limited attic access, it can be difficult to install blown insulation properly. However, there are a few solutions that can help you get the job done. 

1. Cut Through Wall/Ceiling

Cut one or more holes into the ceiling/walls and push the pipe through these holes.

Insulation blower hose inside a hole in the attic blowing fiberglass insulation

It’s important to note that this process can be messy and may require some preparation to protect the interior of the building from the insulation material as it is being blown through the hole.

It’s also important to ensure that the insulation is installed to the recommended density and thickness to ensure optimal energy efficiency and comfort, which is trickier to do when you can’t actually get into the attic.

2. Use a Professional Insulation Contractor

If you’re not comfortable climbing into or around your attic because it’s a bit of a tight squeeze, or you don’t like the thought of cutting holes into your walls or ceilings yourself, then you can hire a professional insulation contractor.

Make sure to inform them that access is difficult beforehand so that they can plan well, and also to give them the opportunity to tell you if they are not equipped for more difficult installations.

3. Use a More Powerful Blower With a Longer Hose

As mentioned earlier, you can get machines that are capable of using hoses longer than 100 ft. So, if you’re doing the job yourself, consider renting a blower with a long hose. This will allow you to reach further into your attic without having to climb around as much.

4. Install Insulation Batts Instead

If getting the hose up to your attic or wielding it once it is in the attic is the difficulty, then you might want to consider batt insulation instead. You lay it by hand, so you won’t have to run the hose or try to maneuver it in a cramped attic.

Batt mineral insulation installed in the attic


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